Positive acting, multiposition detent switch



Dec. 7, 1965 R. HELUS ETAL POSITIVE ACTING, MULTIPOSITION DETENT SWITCH Filed Dec. 15, 1961 United States Patent 3,222,466 POSITIVE ACTING, MULTIPOSITION DETENT SWITCH Richard R. Helus, Canoga Park, and Francis J. Jansen, Los Angeles, Calif., assignors to Radio Corporation of America, a corporation of Delaware Filed Dec. 15, 1961, Ser. No. 159,633 8 Claims. (Cl. 200-16) This invention relates to switches and, in particular, to an improved multiposition switch.

One disadvantage of many prior art multiposition switches is the necessity for precise manual setting of the movable switch mechanism. If the switch is improperly set, the movable mechanism may come to rest in a position where no positive switch contact is made. It is thus necessary for the operator to exercise great care in operating the switch in cases where the reliability of the system is important and is, in part, a function of operator performance.

It is an object of the present invention to provide an improved multiposition switch that does not require precise manual setting.

It is another object of this invention to provide a multiposition detent switch in which the movable mechanism comes to rest in a positive contact position even if the mechanism is manually set ambiguously between switch positions.

These objects are accomplished in a preferred embodiment of the, invention by a switch mechanism movable along a track having a number of spaced notches. The mechanism includes a rotatable member having spaced fingers for engaging the notches. The rotatable member is biased toward the track and constrained to a rest position in which at least two of the fingers engage notches in the track. The mechanism further includes means for cooperating with different switch contacts for different rest positions of the mechanism.

In the accompanying drawing, like reference characters refer to like components, and:

FIGURE 1 is a view in perspective of a preferred embodiment of a mulltiposition switch according to the invention;

FIGURE 2 is a plan view of the switch in which the switch mechanism is illustrated in a stable, rest position;

FIGURE 3 is a partial plan view of the switch in which the switch mechanism is illustrated in an unstable position; and

FIGURE 4 is a cut-away view in perspective illustrating the details of the switch mechanism.

The preferred embodiment of the invention is a linear type switch, where the term linear defines the motion imparted to the switch by an operator. It will be apparent from the description which follows that the invention .in its broader aspects is not limited to use in linear type switches and that various modifications may be made in 'the switch to be described without departing from the spirit of the invention. What is illustrated and will be described is the preferred form of the invention as contemplated for a specific use.

Referring now to the various figures of the drawing and particularly to FIGURES 1 and 4, there is illustrated a frame bent at one edge to form a forward wall 12 adapted to be riveted, bolted or otherwise mounted on a control panel (not shown) or other suitable support. The opposed or rear edge of the frame 10 is bent in the form of a substantially U-shaped portion 14 to which is secured a switch contact assembly 16. The switch contact assembly may be, for example, a contact carrying block of insulating material bolted or riveted to the outer surface of the U-shaped portion 14. The top of the frame 10 has first and second elongated slots or channels 20 and 22 formed therein. A plurality of equally spaced notches 24 are provided in one inner wall of the frame 10 along the length of the elongated slot 20. The frame 10, which preferably is made of metal, such as steel, may be manufactured by first stamping or punching out the channels 20 and 22 and notches 24 and then bending the forward and rear edges to provide a relatively inexpensive apparatus.

The movable mechanism of the switch includes a pair of plate members 26, 28 separated by the frame 10 top and fastened together by means of pins or rivets 30. The top plate 26 has atfixed thereto a handle 34 for moving the switch mechanism to a desired position. The plates 26 and 28 are spaced apart at the forward end of the switch mechanism by means of idler or guide wheels 38 which are located in the channel 22. These wheels 38 are adapted to ride along the walls of the channel 22 and limit movement of the plates 26 and 28 to a direction along the length of the channel 22. The rivets serve as shafts for the guide wheels 38. As illustrated in FIG- URE 2, the inner diameters of the idler wheels 38 are greater than the diameters of the corresponding rivets 30, whereby the wheels 38 fit loosely on the rivets 30 and are free to rotate. The plates 26 and 28 are spaced apart at the rear thereof by means of spacers 40 through which the rivets 30 are fitted. The idler wheels 38 and spacers 40 are .best illustrated in FIGURES 2 and 3.

Positioned between the plates 26, 28 in the channel or slot 20 is a rotatable member 44 having apices 46a 46d projecting from the rotatable member 44 and integral therewith. The apices 46a 46d serve as fingers for engaging the notches 24 in the frame 10. The exact geometrical shape of the rotatable member 44 is not critical and is illustrated by way of example only as being substantially square. The distance between the ends of adjacent fingers should be substantially the same as the distance between the centers of adjacent notches 24 so that the fingers 46a 46d properly engage the notches 24, as illustrated in FIGURE 2.

The finger 4 6a 46d are shaped at the extremities to match propely with the notches 24. The notches 24 may be semi-circular, as illustrated in which case the fingers are rounded at the extremeties and preferably have substantially the same radius of curvature as the notches. Centrally located on the rotatable member 44 is a hub 50 which projects from the top and bottom of the member 44 through tear shaped apertures 48 in the top and bottom plates 26 and 28. A first tension spring 52 is connected between the upper projection of the hub 50 and a tab 54 at the forward end of the top plate 26. A similar tension spring 56 (FIGURE 4) connects the bottom projection of the hub 50 to a similar tab (not shown) on the bottom plate 28. These springs 52 and 56 are under sufficient tension to spring load or bias the rotatable member 44 toward the notched track.

A plurality of pairs 60a 60:2 of normally open switch contacts extends from the switch contact assembly 16 toward the front side wall 12 of the frame 10. In general, there may be one set of switch contacts for each positive setting of the switch mechanism. By positive setting of the switch mechanism is meant any position in which two fingers are engaged with a pair of notches 24, as in FIGURE 2. The upper switch contact of each pair extends through the mounting assembly 16 and emerges at the rear of the assembly. The lower switch contacts of the pairs 60a 6011 may be connected to a common bus in the switch contact assembly 16 and a common lead 64 may be brought out at the rear of the assembly 16. The lower contacts also may extend through the assembly block 16 and be brought out separately at the rear of the assembly 16 if desired or required.

Connections between the switch contacts 60a 6021 and external apparatus to be controlled by these switch contacts may be made at the rear of the switch assembly 16.

Secured to the lower plate 28, and movable therewith, is a body 70 of insulating material (FIGURE 4) which is thinner than the normal open spacing between the top and bottom switch contacts and which moves therebetween when the handle 34 is actuated. Secured to, and extending outward from, the top and bottom surfaces of the body 70 is an electrically conductive button contact 72 adapted to electrically close the pairs of switch contacts successively as the plate members 26, 28 are moved along the channel 22. A portion of the body 70 is broken away in FIGURE 4 to better illustrate the button contact 72. The distance between the outer ends of the button contact 72 preferably is slightly greater than the normal spacing between the lower and upper contacts to assure good physical contact. The ends of the button contact 72 are rounded to provide smooth interaction between the switch contacts and the button contact 72. In those cases wherein it is the function of the switch to connect different switch contacts to ground for different positive settings of the switch mechanism, only a single switch contact of each pair 60a 66in need be provided and the button contact 72 may be used to connect the single switch contacts to ground directly by constructing the button contact 72, plate 70 of an electrically conductive material and grounding the frame 10.

As will be described more fully hereinafter, the movable switch mechanism comprising the plates 26, 28, the rotatable member 44 and the button contact 72 and its support 70 is constrained always to come to a stable rest position, or positive setting, with two adjacent ones of the fingers 46a 46d engaging two adjacent notches 24 in the frame 10. The pairs of switch contacts 60a 60n are spaced along the length of the switch so that the button contact 72 shorts a different pair of contacts 60a 60n for each different positive setting of the switch mechanism. The tension springs 52, 56 spring load the rotatable member 44 and bias the rotatable member 44 toward the notched track. The notches 24 engage the fingers 46a 46d and function as detents to prevent movement of the switch assembly, except when force is applied to the handle 34 by an operator. The manner in which the switch mechanism operates so also always to come to rest in a stable, contact closing position will now be described.

The switch mechanism is illustrated in FIGURE 2 in the left-most position. Fingers 46d and 46c are in engagement with the left-most two notches 24. The contact button 72 then is interposed between the pair of switch contacts 69a to short these contacts electrically. The tear shaped apertures 48 are located in the plates 26, 28 so that the hub 50 is positioned in the forward, narrow portion of the apertures 48 when the mechanism is at rest. The apertures 48 permit the hub 50 and rotatable member 44 to move a slight distance away from the notched track when the switch mechanism is moved in response to external force applied on the handle 34.

Assume now that it is desired to move the switch mechanism to the right one position so as to close the pair of switch contacts tib. As the switch mechanism is moved to the right, the rotatable member 44 pivots about the outer end of the finger 460 as the finger 46c turns in the associated notch 24, and the rotatable member 44 rotates in a clockwise direction (FIGURE 3). During this rotation there is a corresponding movement of the hub 50 and rotatable member 44 away from the notched track. The hub 50 rides along the left side wall of the aperture 48 until the rotatable member 44 reaches a dead-center position. The fingers 46c and 46a then are aligned perpendicular to the notched track. The hub 50 swings toward the right wall of the aperture 48 when the rotatable member 44 is rotated further in a clockwise direction off the dead-center position of unstable equilibrium. The tension in the springs 52, 56 is greatest in the dead-center position of the rotatable member 44. These springs 52, 56 produce a turning moment on the rotatable member 44 and, after the rotatable member 44 passes the dead-center position, the rotatable member 44 is rotated in a clockwise direction under the force of the tension springs 52, 56. The member 44 pivots on the engaged finger 46c and rotates to a rest position wherein the fingers 46b and 460 are engaged with an adjacent pair of notches in the track. The switch mechanism is held stably in this position by the detent action of the notches 24. When the rotatable member 44 has the geometry illustrated, the flat side of the member 44 between the engaged fingers may rest against the side wall of the frame 10 (FIGURE 2) and, in so doing, enhances position stability.

It is unnecessary for the operator to position the switch mechanism precisely to the rest position immediately aforementioned. It is only necessary that the operator move the mechanism sufficiently to rotate the member 44 from the position illustrated in FIGURE 2 to a position past dead center. The tension springs 52, 56 then complete the movement of the switch mechanism by a snap action without external force applied if the operator then releases the handle 34. Of course, the rotatable member 44 will return to its initial position (FIGURE 2) if the handle 34 is released before the rotatable member 44 reaches dead center. The switch mechanism may be moved from any rest position to any other position, depending upon the particular pair of switch contacts it is desired to close, and positive switch action is provided, as described above.

What has been illustrated and described is an improved multiposition switch which increases system reliability by reducing the possibility of human error. This is accomplished by providing a switch which always comes to rest in one of several predetermined positions without the necessity of precise setting by the operator. The switch has the further advantages of simple construction and relatively few components, and adaptability for mass production in that the frame 10 may be manufactured by a simple stamping and bending process.

What is claimed is:

1. The combination comprising: a frame having an elongated slot defining first and second spaced inner walls in said frame; a number of equally spaced notches in one of said walls disposed along the length of said slot; a pair of members separated by said frame and movable together in a direction along the length of said slot, each of said members having an aperture therein; a rotatable member positioned in said slot between said pair of members and having a hub which projects through each 'said aperture, said rotatable member having spaced fingers for engaging said notches; and bias means coupled between said hub and said pair of members and urging said rotatable member toward said one of said walls.

2. The combination comprising: a frame having a slot therein defining first and second spaced walls in said frame; a number of equally spaced notches in one of said walls disposed in a direction along the length of said slot; a pair of members separated by said frame, normal to said walls, and restricted to movement in a direction along the length of said slot; a rotatable member positioned in said slot between said pair of members and having a hub which is normal to, and engaged by, said pair of members, said rotatable member having a number of spaced fingers for engaging said notches, the spacing between the ends of adjacent said fingers being equal substantially to the spacing between adjacent ones of said notches; and bias means operatively connected to said hub for urging said rotatable member toward said one of said walls.

3. The combination comprising: a frame having an elongated slot therein defining first and second spaced walls in said frame; a number of equally spaced notches in one of said walls disposed along the length of said slot; a pair of apertured members separated by said frame, normal to said walls, and movable together in a direction along the length of said slot; a rotatable member positioned in said slot between said apertured members and having a hub which projects through an aperture in each of said apertured members, said rotatable member having a number of spaced fingers for engaging said notches, the spacing between the ends of adjacent said fingers being equal substantially to the spacing between adjacent ones of said notches; and a pair of springs each connected between a different end of said hub and the associated one of said apertured members for biasing said rotatable member toward said one of said walls.

4. The combination comprising: a frame having a slot therein defining first and second spaced walls in said frame; a number of equally spaced notches in one of said walls disposed along the length of said slot; a pair of apertured members separated by said frame, normal to said walls, and movable together in a direction along the length of said slot; a rotatable member positioned in said slot between said apertured members and having a hub which projects through an aperture in each of said apertured members, said rotatable member having a number of spaced fingers for engaging said notches, the spacing between the ends of adjacent said fingers being equal substantially to the spacing between adjacent ones of said notches; and a pair of springs each connected between a different projecting end of said hub and a point on the associated one of said apertured members near said one of said walls so that each of said springs is substantially normal to said walls, said springs acting to bias said rotatable member toward said one of said walls.

5. The combination comprising: a frame having an elongated slot defining first and second spaced walls in said frame; a number of equally spaced notches in one of said walls disposed along the length of said slot; an elongated channel in said frame parallel to said slot; a pair of apertured members separated by said frame; a pair of guide wheels positioned in said channel parallel to said members and rotatable about pins through said apertured members for limiting movement of said members to a direction along the length of said channel; a rotatable member positioned in said slot parallel to said apertured members and having a hub which projects through an aperture in each of said apertured members, said rotatable member having spaced fingers for engaging said notches, the distance between the ends of adjacent ones of said fingers being equal to the spacing between adjacent ones of said notches; and bias means coupled between each end of the hub and the respective apertured member and urging said rotatable member toward said one of said walls.

6. The combination comprising: a frame having an elongated slot therein definingfirst and second spaced walls in said frame; a number of equally spaced notches in one of said walls disposed along the length of said slot; a pair of apertured members separated by said frame,

normal to said walls, and movable together in a direction along the length of said slot; a rotatable member positioned in said slot between said apertured members and having a hub which projects through an aperture in each of said apertured members, said rotatable member having a number of spaced fingers for engaging said notches, the spacing between the ends of adjacent said fingers being equal substantially to the spacing between adjacent ones of said notches; a pair of springs each connected between a different projecting end of said hub and a point on the associated one of said apertured members near said one of said walls so that each of said springs is substantially normal to said walls, said springs acting to bias said rotatable member toward said one of said walls; a plurality of switch contacts positioned along the length of said frame; and contact engaging means mounted on one of said apertured members for engaging said contacts sequentially as said apertured members are moved in a direction along the length of said slot.

7. The combination as claimed in claim 6 wherein said switch contacts are positioned so that a switch contact is engaged by said contact engaging means when an adjacent pair of said fingers is engaged with an adjacent pair of said notches.

8. The combination comprising: a frame having an elongated slot therein defining first and second spaced walls in said frame; a number of equally spaced notches in one of said walls disposed along the length of said slot; a pair of apertured members separated by said frame, normal to said walls, and movable together in a direction along the length of said slot; a rotatable member positioned in said slot between said apertured members and having a hub which projects through an aperture in each of said apertured members, said rotatable member having a number of spaced fingers for engaging said notches, the spacing between the ends of adjacent said fingers being equal substantially to the spacing between adjacent ones of said notches; a pair of springs each connected between a different projecting end of said hub and a point on the associated one of said apertured members near said one of said walls so that each of said springs is substantially normal to said walls, said springs acting to bias said rotatable member toward said one of said walls; a plurality of switch contacts positioned along the length of said frame; contact engaging means mounted on one of said apertured members for engaging said contacts sequentially as said apertured members are moved in a direction along the length of said slot; and a handle attached to one of said apertured members for manually moving said apertured members in a direction along the length of said slot.

References Cited by the Examiner UNITED STATES PATENTS 601,588 3/1898 Pool 200-16 1,110,616 9/1914 Fargeson 74-422 1,908,204 5/1933 Winning 200--16 2,521,561 9/ 1950 Batcheller 2006 2,951,130 8/1960 Mason 200--166 X 3,146,320 8/1964 Wang et al. 200-16 X KATHLEEN H. CLAFFY, Primary Examiner. BERNARD A. GILHEANY, Examiner. 

1. THE COMBINATION COMPRISING: A FRAME HAVING AN ELONGATED SLOT DEFINING FIRST AND SECOND SPACED INNER WALLS IN SAID FRAME; A NUMBER OF EQUALLY SPACED NOTCHES IN ONE OF SAID WALLS DISPOSED ALONG THE LENGTH OF SAID SLOT; A PAIR OF MEMBERS SEPARATED BY SAID FRAME AND MOVABLE TOGETHER IN A DIRECTION ALONG THE LENGTH OF SAID SLOT, EACH OF SAID MEMBERS HAVING AN APERTURE THEREIN; A ROTATABLE MEMBER POSITIONED IN SAID SLOT BETWEEN SAID PAIR OF MEMBERS AND HAVING A HUB WHICH PROJECTS THROUGH EACH SAID APERTURE, SAID ROTATABLE MEMBER HAVING SPACED FINGERS FOR ENGAGING SAID NOTCHES; AND BIAS MEANS COUPLED BETWEEN 